Huang Shizhi, Yang Junfeng, Ma Luxiang, Ding Jingyi, Wang Xusheng, Peng Chengyuan, Zhao Binglu, Cao Mengxiong, Zheng Junrong, Zhang Xin-Xiang, Chen Jitao
Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China.
Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.
Adv Sci (Weinh). 2021 Oct;8(19):e2101584. doi: 10.1002/advs.202101584. Epub 2021 Aug 3.
A disordered phase in Li-deposit nanostructure is greatly attractive, but plagued by the uncontrollable and unstable growth, and the nanoscale characterization in the structure. Here, fully characterized in cryogenic transmission electron microscopy (cryo-TEM), more robust amorphous-Li (ALi) clusters are revealed and effectively regulated on heteroatom-activating electronegative sites and an advanced solid electrolyte interphase (SEI) layer. Heteroatom-activating electronegative sites capably enhance the electrostatic interaction of Li and heteroatom-doping graphene-like film (HDGs), meaning lower Li diffusion barrier and larger binding energy that is confirmed by small nucleation overpotentials of 13.9 and 10 mV at 0.1 mA cm in the fluoroethylene carbonate-adding ester-based (FEC-ester) and LiNO -adding ether-based (LiNO -ether) electrolytes. Orderly multilayer SEI structure comprised of inorganic-rich components enables fast ion transports and durable capabilities to construct highly reversible and long-term plating/stripping cycling. ALi cluster anodes exhibit non-crystalline morphologies and perform ultrastable dendrite-free cycling over 2800 times. Stable ALi clusters are also grown in LiFePO (LFP) (LFP-ALi-HDGs-N||LiFePO [LFP]) full cells with advantageous capacities up to 165.5 and 164.3 mAh g in these optimized electrolytes at 0.1 C; the remarkable capacity retentions maintain to 93% and 91% after 150 cycles at 0.2 C. Structure viability, electrochemical reversibility, and excellent performance in ALi clusters are effectively regulated.
锂沉积纳米结构中的无序相极具吸引力，但却受到生长不可控和不稳定以及结构纳米级表征的困扰。在此，通过低温透射电子显微镜（cryo-TEM）进行了全面表征，揭示了更稳定的非晶态锂（ALi）团簇，并在杂原子活化的电负性位点和先进的固体电解质界面（SEI）层上对其进行了有效调控。杂原子活化的电负性位点能够增强锂与杂原子掺杂类石墨烯薄膜（HDGs）之间的静电相互作用，这意味着锂的扩散势垒更低且结合能更大，这在含氟碳酸乙烯酯的酯基（FEC-酯）电解质和添加LiNO₃的醚基（LiNO₃-醚）电解质中，在0.1 mA cm⁻²时13.9和10 mV的小成核过电位得到了证实。由富含无机成分组成的有序多层SEI结构能够实现快速离子传输，并具有构建高度可逆和长期电镀/剥离循环的持久能力。ALi团簇阳极呈现非晶态形态，并且能够进行超过2800次的超稳定无枝晶循环。在这些优化的电解质中，在0.1 C下，稳定的ALi团簇也生长在磷酸铁锂（LFP）（LFP-ALi-HDGs-N||LiFePO₄ [LFP]）全电池中，具有高达165.5和164.3 mAh g⁻¹的有利容量；在0.2 C下经过150次循环后，显著的容量保持率分别维持在93%和91%。ALi团簇中的结构可行性、电化学可逆性和优异性能得到了有效调控。
